This invention concerns archery devices such as bows and cross bows in which limbs are flexed to create stored energy, which energy is released at firing to accelerate the arrow nocked to a bowstring connected to the limb tips.
In copending application Serial No. 871,793 filed June 9, 1986, of the present inventor, there is disclosed an arrangement for increasing the arrow accelerating forces able to be generated using separate bending and launching bowstrings. In that arrangement successive draws of the bending bowstring act to bend the limbs, with a bending mechanism affording a mechanical advantage to the user in drawing the bending bowstring to bend the limbs. The separate launching bowstring directly receives the stored energy of the flexed limbs at firing and the arrow is thus nocked to the launching bowstring.
In that arrangement, several successive draws of the bending bowstring are required to fully bend the limbs since the leveraging system, in reducing the draw effort necessitates a much greater draw distance over the normal range of drawing movement possible by an archer.
This necessitates the added complexity of a ratcheting-latching mechanism to allow the bending accomplished by each draw to be held and increased bending achieved by each successive draw.
While greatly increased accelerating forces are made possible by this arrangement, limitations are imposed by the conventional pushing or thrust mode used to launch the arrow. That is, the arrows are distorted by the application of the compressive accelerating forces at the rear end of the arrow which tend to compress the arrow causing it to bend. For the very high forces able to be generated in that device, this distortion tends to become excessive, and represents a practical limitation on the velocity achievable.
Even for conventional bows, the design of the arrow is dictated by the need to prevent excessive shaft bending resulting from the compressive load applied to the arrow. The tumbling tendency of the arrow when launched from the rear requires additional design effort. The tendency for bending and tumbling adversely affects the flight characteristics of the arrow, reducing accuracy and velocity. Finally, the length of the arrow is dictated by the practical draw length of an archer rather than aerodynamic or other performance considerations.
Accordingly, it is an object of the present invention to provide a bending-launching dual bowstring archery device in which a separate latching mechanism and successive draws are not required while allowing a leveraged action of the bending bowstring, to enable much higher peak accelerating forces to be exerted on the arrow.
It is another object of the present invention to provide an arrow launching system in which very high accelerating forces may be applied to the arrow, without any distortion thereof.
It is yet another object of the present invention to provide a front launch archery system for projectiles to eliminate the disadvantages of conventional archery devices.